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Directed Light Fabrication Of Refractory Metals And Alloys
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Book Synopsis Directed Light Fabrication of Refractory Metals and Alloys by :
Download or read book Directed Light Fabrication of Refractory Metals and Alloys written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report covers deposition of refractory pure metals and alloys using the Directed Light Fabrication (DLF) process and represents progress in depositing these materials through September 1998. In extending the DLF process technology to refractory metals for producing fully dense, structurally sound deposits, several problems have become evident. (1) Control of porosity in DLF-deposited refractory metal is difficult because of gases, apparently present in commercially purchased refractory metal powder starting materials. (2) The radiant heat from the molten pool during deposition melts the DLF powder feed nozzle. (3) The high reflectivity of molten refractory metals, at the Nd-YAG laser wavelength (1.06[micro]m), produces damaging back reflections to the optical train and fiber optic delivery system that can terminate DLF processing. (4) The current limits on the maximum available laser power to prevent back reflection damage limit the parameter range available for densification of refractory metals. The work to date concentrated on niobium, W-25Re, and spherodized tungsten. Niobium samples, made from hydride-dehydride powder, had minimal gas porosity and the deposition parameters were optimized; however, test plates were not made at this time. W-25Re samples, containing sodium and potassium from a precipitation process, were made and porosity was a problem for all samples although minimized with some process parameters. Deposits made from potassium reduced tungsten that was plasma spherodized were made with minimized porosity. Results of this work indicate that further gas analysis of starting powders and de-gassing of starting powders and/or gas removal during deposition of refractory metals is required.
Book Synopsis Directed Light Fabrication of Refractory Metals by :
Download or read book Directed Light Fabrication of Refractory Metals written by and published by . This book was released on 1997 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directed Light Fabrication (DLF) is a metal, rapid fabrication process that fuses metal powders to full density into a solid replica of a computer modeled component. It has been shown feasible for forming nearly any metal and also intermetallics to near net shape with a single process. DLF of refractory pure metals is feasible, bypassing the extensive series of conventional processing steps used for processing these high melting point materials. Tungsten, tantalum, and rhenium were processed and show a continuous resolidified microstructure. Porosity was a problem for the tantalum and rhenium powders produced by chemical reduction processes but not for the tungsten powder spherodized in a plasma arc. Chemical analysis of powder compared to the DLF deposit showed reductions in carbon, oxygen and hydrogen, indicating that process parameters may also be optimized for evolution of residual gases in the deposits.
Book Synopsis Materials Analysis of Deposits Made by the Directed-light Fabrication Process by :
Download or read book Materials Analysis of Deposits Made by the Directed-light Fabrication Process written by and published by . This book was released on 1996 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The directed-light fabrication (DLF) process is a unique method of forming three-dimensional objects by fusing airborne powders in the focus of a laser beam. This process bypasses conventional ingot processing steps of casting, homogenization, extrusion, forging, and possibly some or all of the required machining. It provides a new ''near-net-shape'' fabrication technology for difficult-to-fabricate materials such as refractory metals, metal composites, intermetallics, ceramics, and possibly superconductors. This project addresses the solidification behavior during DLF processing to characterize the technique in terms of solid/liquid interface characteristics, cooling rates, and growth rates. Materials studied were Ag-Cu, Fe-Ni, 316SS, and Al-Cu.
Book Synopsis Fabrication of Refractory Metals by : Walter D. Wilkinson
Download or read book Fabrication of Refractory Metals written by Walter D. Wilkinson and published by . This book was released on 1970 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rapid Fabrication of Materials Using Directed Light Fabrication by :
Download or read book Rapid Fabrication of Materials Using Directed Light Fabrication written by and published by . This book was released on 1997 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directed light fabrication (DLF) is a rapid fabrication process that fuses gas delivered metal powders within a focal zone of a laser beam to produce fully dense, near-net shape, 3-dimensional metal components from a computer generated solid model. Computer controls dictate the metal deposition pathways, and no preforms or molds are required to generate complex sample geometries. The focal zone of the laser beam is programmed to move along or across a part cross-section, and coupled with a multi-axis sample stage, produces the desired part. By maintaining a constant molten puddle within the focal zone, a continuous liquid/solid interface is possible while achieving constant cooling rates that can be varied between 10 to 104 K s−1 and solidification growth rates (that scale with the beam velocity) ranging up to 102 m s−1. The DLF technique offers unique advantages over conventional thermomechanical processes in that many labor and equipment intensive steps can be avoided. Moreover, owing to the flexibility in power distributions of lasers, a variety of materials can be processed, ranging from aluminum alloys to rhenium, and including intermetallics such as Mo5Si3. As a result, the rapid fabrication of conventional and advanced materials are possible.
Book Synopsis Refractory Metals and Alloys III: Applied Aspects by : Robert Isaac Jaffee
Download or read book Refractory Metals and Alloys III: Applied Aspects written by Robert Isaac Jaffee and published by . This book was released on 1966 with total page 1048 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Refractory Metals and Alloys written by and published by . This book was released on 1966 with total page 1048 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effect of Fabrication History and Microstructure on the Mechanical Properties of Refractory Metals and Alloys by : Albert G. Imgram
Download or read book The Effect of Fabrication History and Microstructure on the Mechanical Properties of Refractory Metals and Alloys written by Albert G. Imgram and published by . This book was released on 1963 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the present knowledge concerning the relationship among fabrication history, metallurgical structure, and the mechanical properites of the refractory metals columbium, tantalum, bolybdenum, and tungsten, and their alloys. These are the refractory metals currently reveiveing the most attention for aerospace applications, and are therefore the materials considered in this survey. The report is organized into three main sections, titled ''Fabrication'', ''Microstructure and Alloying'', and ''Interstitial Impurities''. The data presented were selected as those which best illustrate the topics discussed. Descriptions of the metaljurgical principles involved are included. Suggestions for optimizing mechanical properties by controlling metallurgical structure are made where possible. (Author).
Book Synopsis Solidification Behavior During Directed Light Fabrication by :
Download or read book Solidification Behavior During Directed Light Fabrication written by and published by . This book was released on 1995 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directed light fabrication (DLF) is a process that fuses gas delivered metal powders within a focal zone of a laser beam to produce fully dense, 3-dimensional metal components. A variety of materials have been processed with DLF, ranging from steels to tungsten, and including intermetallics such as NiAl and MoSi2. To evaluate the processing parameters and resulting microstructures, solidification studies have been performed on defined alloy systems. For example, solidification cooling rates have been determined based upon secondary dendrite arm spacings in Fe-based alloys. In addition, eutectic spacings have been used to define growth velocities during solidification. Cooling rates vary from 101-105 K s−1 and growth rates vary between 1--50 mm s−1. As a result, process definition has been developed based upon the microstructural development during solidification. The materials explored were Ag-19Cu, Fe-24.8Ni, 316 stainless steel, Al-33Cu, W, MoSi2 and NiAl.
Book Synopsis Free-form Processing of Near-net Shapes Using Directed Light Fabrication by :
Download or read book Free-form Processing of Near-net Shapes Using Directed Light Fabrication written by and published by . This book was released on 1997 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directed light fabrication (DLF) is a rapid fabrication process that fuses gas delivered metal powders within a focal zone of a laser beam to produce fully dense, near-net shape, three-dimensional metal components from a computer generated solid model. Computer controls dictate the metal deposition pathways, and no preforms or molds are required to generate complex sample geometries with accurate and precise tolerances. The DLF technique offers unique advantages over conventional thermomechanical processes or thermal spray processes in that many labor and equipment intensive steps can be avoided to produce components with fully dense microstructures. Moreover, owing to the flexibility in power distributions of lasers, a variety of materials have been processed, ranging from aluminum alloys to tungsten, and including intermetallics such as Mo5Si3. Since DLF processing offers unique capabilities and advantages for the rapid fabrication of complex metal components, an examination of the microstructural development has been performed in order to define and optimize the processed materials. Solidification studies of DLF processing have demonstrated that a continuous liquid/solid interface is maintained while achieving high constant cooling rates that can be varied between 10 to 105 K s−1 and solidification growth rates ranging up to the 10−2 m s−1.
Author :American Society of Mechanical Engineers. Solar Energy Division. Conference Publisher : ISBN 13 : Total Pages :524 pages Book Rating :4.3/5 (91 download)
Book Synopsis Solar Engineering by : American Society of Mechanical Engineers. Solar Energy Division. Conference
Download or read book Solar Engineering written by American Society of Mechanical Engineers. Solar Energy Division. Conference and published by . This book was released on 1998 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Special Issue on Refractory Metals and Alloys by :
Download or read book Special Issue on Refractory Metals and Alloys written by and published by . This book was released on 1994 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Properties of Refractory Metals by : Walter D. Wilkinson
Download or read book Properties of Refractory Metals written by Walter D. Wilkinson and published by . This book was released on 1969 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Solid Freeform Fabrication Symposium Proceedings by :
Download or read book Solid Freeform Fabrication Symposium Proceedings written by and published by . This book was released on 1997 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Materials and Manufacturing Processes. Special Issue on Refractory Metals and Alloys. Volume 9, Number 6 by : T. S. Srivatsan
Download or read book Materials and Manufacturing Processes. Special Issue on Refractory Metals and Alloys. Volume 9, Number 6 written by T. S. Srivatsan and published by . This book was released on 1994 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of Fabrication Process for Metallic Fibers of Refractory Metal Alloys Final Report by :
Download or read book Development of Fabrication Process for Metallic Fibers of Refractory Metal Alloys Final Report written by and published by . This book was released on 1970 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Directed Light Fabrication--a Laser Metal Deposition Process for Fabrication of Near-net Shape Components by :
Download or read book Directed Light Fabrication--a Laser Metal Deposition Process for Fabrication of Near-net Shape Components written by and published by . This book was released on 1997 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Directed Light Fabrication (DLF) is a direct metal deposition process developed at LANL. A solid computer model is used to generate a tool path that moves a laser beam within the required part boundaries to deposit a planar metal layer (about .1 mm thick) which is successively stacked to build the entire part. Metal powder particles are introduced into the laser focal zone where they melt and then solidify to produce a fully dense deposited layer. In a single processing step, metal components are formed eliminating the series of processing steps required by conventional processing such as forging, stamping, casting, etc. The accomplishments of this project have been as follows; (1) advancement of the technology from 3 axes of motion to 5 axes of motion producing true three-dimensional components and assemblies; (2) development of a workable machine for accurate powder delivery, powder recycle, and gas recycle; and (3) demonstrated feasibility for processing almost any metal and intermetallic compound.
